When it comes to gas detection, shipowners have plenty of incentives to go beyond what laws and regulations require of them.
All fleet operators are required by law to equip their vessels with gas detection equipment. However, not all such systems are created equal; the regulatory landscape is complex and many shipowners struggle to maintain a coordinated approach, both in terms of usage, maintenance and procurement.
Lack of precision adds cost and reduces safety. Additionally, many contractors require their suppliers to exceed the minimum safety requirements, meaning a lesser gas detection system can disqualify a vessel from a contract. Thus, shipowners have plenty of incentive to go beyond what they are required to by law.
1. Suitability – Use the Appropriate Equipment
The cargo and ship type will determine which detector with which sensor will adequately perform the correct detection. For example, a chemical tanker represents a different scenario than a crude oil tanker does.
Sometimes yard supply (prior to launch) install generic instruments that only loosely match the ship’s requirements. If a vetting is coming up, the crew might discover that they need to add equipment to their gas detection kit. Typically, this forces them to shore where they visit with a local supplier. He or she may give them an instrument that perhaps only partially covers their needs.
By outsourcing your gas detection requirements to an expert, all you have to do is provide a description of your ship(s), your cargo, the regulations you need to adhere to and so forth. They will then evaluate your needs and suggest a set of detectors and sensors that precisely match your requirements.
The Bruusgaard System.
Read more: Gas Detection at Sea: The Bruusgaard System Explained
2. Perform Testing and Maintenance on Board
Gas detection equipment requires periodic maintenance and testing. Most shipowners ship their equipment to onshore service facilities, but this is not a requirement by law. Some suppliers, however, insist on taking equipment to shore for service. Shipowners will have to comply in order to gain a valid stamp of approval.
Shipping onshore is unnecessary. To the contrary, there actually is a strong case for performing testing and maintenance on board.
First of all, you’re required to be able to calibrate on board. Secondly, by doing everything on board, you get more familiar with the equipment. Inhouse expertise can be crucial in the event of a situation that calls for a double-check of the instrument, or if you’re faced with an unannounced vetting. In these situations, you will have a problem if you’re unable to calibrate your equipment.
A third benefit of inhouse servicing, is that the crew who is tasked with maintaining and testing the equipment (typically the captain, the chief officer or the chief engineer), can communicate directly with the supplier. This provides optimal knowledge and familiarity with the equipment.
3. Sampling Strategy and Equipment
Sampling is extremely important to crew safety. Before entering a manhole, a thorough mapping of the enclosed space should be performed.
Strategy/Method
Mechanical ventilation is an effective tool, but gases can remain trapped in pockets, either close to the floor or close to the ceiling. Therefore, perform sampling at different locations, ideally in three dimensions. As a minimum, make sure to get a read on the lower, the middle and the top layer of the atmosphere.
Sampling is to be undertaken:
- Always prior to entry.
- Continuously or at rapid intervals during the work.
- Periodically during ventilation, in order to monitor the flushing itself and the risk of explosion.
Before any work is done in a hazardous area, arrange a run-through with all relevant personnel. Remind them of the routines and safety precautions. Calibrate your equipment as needed.
Equipment
A prerequisite for effective sampling is appropriate equipment of trade approved quality, like tubes with sufficient reach. It is important that all equipment intended for atmosphere analysis is:
- Suited for the task
- Type approved
- Properly maintained
- Frequently controlled against standard samples
Finally, the results of the measurements should be controlled by at least two competent persons.
What to Measure for?
You need to be able to detect:
- Oxygen
- Toxic gases
- Hydrocarbons (explosive gases)
Certain vessels, like LPG or chemical tankers need more sophisticated detection diversity capabilities. A Riken Keiki GX-6000 will meet most such demands.
4. Knowing How to Interpret Results
When sampling for a particular gas, certain substances can interfere and skew the results of the reading. In such cases, it is necessary to employ correctional factors and perhaps deactivate some other sensors.
Gas detection at sea is not done for research purposes; you simply measure to determine whether a space is safe or not. In most cases, all you need your gas detector to provide is either a red or a green light.
Detector tubes cost less, but can be intricate in use. They also yield high-resolution readings that often exceed what really is required. An instrument like the Riken Keiki GX-6000, on the other hand, returns either a green or a red light. It simplifies and speeds up the sampling process substantially.
5. Check and Recondition After Use
After sampling with an instrument, you should re-check before further use. There are a couple of recommended steps to take:
- Check filter status, replace if contaminated.
- Check the batteries.
- Recondition the exposed parts of the apparatus:
- Let them dry.
- Flush tubes and inlet compartments with air or/and nitrogen to clean out residues.
Key Takeaway – Get on Board with Gas Detection
Gas detection is a complex discipline, but there is a way to make it simpler, safer and more cost-effective. Getting an expert partner involved can help you do more with less, because you will be able to:
- Eliminate surplus equipment – and associated servicing.
- Perform key operations on board.
- Become self-sufficient in terms of testing and maintenance.
- Rely on independently verified check lists.
- Improve crew competence and safety.
- Achieve compliance with all relevant stakeholders.
- Clear vettings.
- Cut direct costs (maintenance).
- Cut indirect costs (improved operations and safety, and no need to dock and interrupt transit).